Railway traffic controlling apparatus



Jan. 5, 1943. J. J. vANHoRN l 2,307,476

RAILWAY TRAFFIC CONTR'OLLING APPARATUS I mwN Bib www N ,0 Nw .NQ www sm E@ m wj MANS EN Patented Jan. `5, 1943 ENCE.

RAILWAY TRAFFIC CONTROLLING APPARATUS James J. Vanhorn, Swissvale, Pa., assigner to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application June 22, 1940, Serial No. 341,923

2 Claims.

My invention relates to railway trac controlling apparatus, and more particularly to approach locking apparatus for use in interlocking systems for railroads, for locking a track switch against operation under certain conditions when a signal governing the movement of traffic over the switch is manually put to stop. The purpose of such locking is to prevent movement of the switch when a train is approaching at such speed that it cannot be readily stopped without overrunning the switch.

In such situations it is customary to normally permit movement of the switch only when the stretch of track leading to the switch is unoccupied, and when a signal located some distance from the switch is conditioned to display a restrictive indication.

It has heretofore been proposed to provide a line circuit controlled by track relays of the track sections in the track stretch leading to the switch to provide means to detect whether the track stretch is occupied or not. It has also been proposed to provide another line circuit leading from the distant signal to the control tower or other point from which the switch is controlled to indicate whether the distant signal is displaying a restrictive indication or not.

The approach portion or Zone of the track stretch which must be checked for occupancy is relatively long, while the distant signal which must be checked is located a considerable distance from the track switch. Accordingly the line circuits ior checking the distant signal and occupancy of the approach portion of the track stretch are necessarily quite long, and installation and maintenance of the wires for these circuits involves considerable expense. Obviously there would be a substantial saving if the same line circuit could be employed to check both the signal and occupancy of the track stretch.

It is an object of this invention to provide improved equipment of the type described which employs but a single line circuit to indicate at a remote point the condition of a signal and also of a stretch of railway track.

A further object of the invention is to provide an improved switch control system requiring less equipment than the systems heretofore known` Another object of the invention is to provide improved means employing a single line circuit to indicate at a remote point the condition of a signal and of occupancy of a track stretch, the equipment being arranged so that each of these conditions may be indicated independently of the other. i

track A, and a siding or diverging track B which is connected with the main track by means of a Other objects of the invention and features of novelty will be apparent from the following description taken in connection with the accompanying drawing.

I shall describe one form of apparatus embodying my invention and shall then point out the novel features thereof in claims.

In the drawing the single figure is a. diagram of a stretch of railway track equipped with one form of apparatus embodying my invention.

Referring to the drawing there is shown therein a stretch of railroad track having a main track switch W. The switch W is moved between the normal and reverse positions by a power operated switch machine SM which may be of any suitable construction well-known in the art.

The main track A has track rails I and 2 which are divided by insulated joints 3 into the usual track sections, which are here identified as sections IIJT, I IT and lZT. The track sections IGT, I IT and IRT-together constitute an approach stretch or approach zone, while a detector section I3T is provided and includes the switch W and the portions of the tracks A and B adjacent to the switch.

Each of the track sections is provided with track circuit apparatus which may be of any well-known type. As shown each section has a track battery TB connected across the rails of the section at one end of the section, and a track relay TR connected across the rails of the section at the other end of the section.

The main track A vis, provided with wayside signals which govern movement of trains through the track stretch. The wayside signals may be of any suitable type, and are here shown as being of the color light type. Only the signals governing movement of trains from left to right have been shown, but it should be understood that other signals may be provided to govern movement of trains from right to left if movement of trains in this direction is contemplated.

The home signal at the switch W has an upper portion designated SA which governs movement of trains through the track A across the switch W, and a lower portion designated SB which governs movement of trains from the main track A across the switch W to the side or branch track B.

The signal SA has a green or clear lamp, a yellow or caution lamp, and a red or stop lamp, while the signal SB has a yellow or proceed lamp and a red or stop lamp.

A distant signal SD is located some distance SD has a green or clear lamp, a yellow or caution lamp, and a red or stop lamp.

The distant signal SD is controlled in any desired-manner by trafc conditions in advance of the signal so that the signal will display its red or stop indication when a train is present in either of the track sections ||T or |2T. The signal SD is also controlled in accordance with the indication displayed by the signal SA so that when the signal SA is displaying its red or stop indication the signal SD will display its yellow or caution indication. A

The means by which the signal SD is controlled in accordance with traillc conditions in advance, and by the indication displayed by the signal SA, is old and well-known in the art and is not a part -of this invention, and has not been shown in order to simplify the disclosure.

Similarly, the signal SA is controlled by trafc conditions in advance of the signal, While manually operated means is provided for also controlling the signals SA and SB. The means by which these signals are controlled is old and Well-known in the art and has not been shown in order to simplify the disclosure. l

A polarized switch control relay WR is provided to control the switch machine SM, and the supply of energy of normal or reverse polarity to the winding of the relay WR is controlled by appropriate means, such as a manually controlled switch control lever L. The lever L may be located at any convenient point, as for example in a signal control tower, and may form part of an interlocking machine.

The approach locking 0f the track switch is effected by means of an approach locking relay H which controls the circuit of the switch control relay WR to permit energization of the relay WR only when the relay H is energized.

The circuit of the switch control relay WR is t also controlled by the track relay ISTR for the detector section |3T.

The circuit of the winding of the approach locking relay I-I is controlled by relays GC and. JC, and this invention is directed particularly to the means for energizing the relays GC and JC. The.

other portions of the switch control system may be arranged in any manner Well-known in the art, and only as much of the apparatus has been shown in the drawing and is described in this specification as is essential to the understanding r of this invention.

A pair of line wires and 2| substantially coextensive with the track sections ||T and IZT are provided. As hereinafter explained in detail there is means governed by the track relays IUTR 2 and ||TR of the track sections of the approach zone and by the distant signal SD for supplying coded current over the line wires to energize the code following relay CR.

The system employs a code transmitter CT havto provide '75, 120 and 180 energy impulses per minute which are separated by time intervals of equal `duration during which the supply of energy is interrupted.

One terminal of the battery 24C is connected directly to line Wire 2 I, while the other terminal of the battery is connected to a -contact 35D which is controlled in accordance with the aspect displayed by the distant signal SD. The contact 35D is controlled in such manner that it is picked up when the signal SD is displaying its clear indication, and is released when this signal is displaying either its caution or its stop indication.

The contact 35D when picked up establishes connection from a terminal of the battery to the contact of the code transmitter CT, while the contact 35D when released establishes connection from the battery terminal to the contacts 15 and |20 of the code transmitter.

The circuits of the contacts of the code transmitter are controlled by the contacts 25 and 26 of the track relays |0TR and ITR in such manner that connection is established from the code transmitter contacts |20 and |80 to the line Wire 20 only when the track relay contacts 25 and 26 are both picked up, while connection is established from contact 15 to the line Wire 20 when the contact of either of the track relays |0TR or IITR is released.

The relay CR has a Contact ||9 which controls the supply of energy from a local source of direct current, the terminals of which are designated B and C, to the primary Winding |22 of the decoding transformer DT, while contact |2| recties the current supplied from the transformer secondary Winding |23 to the Winding of the relay RA.

The decoding transformer DT has a secondary winding |24 from which energy is supplied through resonant rectifier units RUB and RUC to the windings of relays RB and RC.

The resonant rectifier units RUB and RUC each include a capacitor and an inductance which are selected and proportioned so that the unit will pass a substantial value of energy only when the frequency of the current induced in the secondary Winding |24 is that which is present when the' relay CR is responding to energy of a particular code frequency. The unit RUB is arranged so that it will pass energy of substantial value when the relay CR is responding to energy of the code frequency, while the unit RUC is arranged so that it will pass energy of substantial value when the relay CR is responding to energy of the code frequency. Each of the resonant rectifier units includes a rectier for converting into direct current the alternating current energy which is supplied through the unit.

The circuit for supplying energy from the winding |24 of the transformer DT to the resonant unit RUB is controlled by contact |26 of the relay RC and is complete only when contact |26 is released. Accordingly when the relay CR is responding to energy of the 180 code frequency and the relay RC is picked up, the circuit for supplying energy to the resonant unit RUB is interrupted and there is no possibility that energy will be supplied through this unit to the Winding of the relay RB to pick up this relay.

This arrangement is advantageous as a resonant unit designed to permit energy of 120 code frequency to pass may pass sufficient energy of the 180 code frequency to pick up a relay. On the other hand, a unit designed to pass energy of 180 code frequency will not pass substantial values of current of the lower code frequency so there is no possibility of improper energization of the relay RC when the relay CR is responding to energy of 120 code frequency, and by interrupting the circuit of the resonant unit RUB when the relay RC is picked up the Apossibility of improper energization of the relay RB is eliminated.

Similarly the circuit for supplying energy from the Winding |23 of the transformer DT to the winding ci the relay RA is controlled by a contact I 21 of relay RB and a contact |28 of the relay RC. Accordingly, when the code following relay CR is responding to energy of either the 120 or the 180 code frequency the circuit of the winding of the relay RA is interrupted, While the circuit of the winding of the relay RA is complete when the relays RB and RC are released.

The relays RA and RB have contacts and |3| which when picked up establish circuits through which energy may be supplied to the winding of relay GC. The circuit of the winding of the relay GC is also controlled by contact 31C which is governed in accordance with the aspects displayed by the home signals SA and SB. This contact is controlled in such manner that it is closed when and only when the signals SA and SB are both displaying stop indications.

The relays RB and RC have contacts |33 and |34 which when picked up establish circuits through which energy may be supplied from the local source to the winding of the relay JC. The circuit of the winding of the relay JC is also controlled by contact 28 of the track relay |2TR with the result that this circuit is interrupted whenever the track section I2T is occupied.

The equipment is shown in the condition which it assumes when the track stretch is vacant and the home signal SA and the distant signal SD are both displaying clear indications.

As the track stretch is vacant the contacts of the track relays IDTR, ||TR and |2TR are picked up, while as the signal SD is assumed to be displaying its clear indication the contact 35D is picked up with the result that energy is supplied from the battery 24C over the line wires to the winding of the code following relay CR through the circuit which includes the 180 contact of the code transmitter CT. The circuit for supplying energy from the battery 24C to the relay CR is traced from one terminal of the battery through line wire 2|, winding of relay CR, line wire 20, front contact 26 of relay ITR, front contact 25 of relay IBTR, contact 180 of code transmitter CT, and front contact 35D to the other terminal of the battery.

As a result, therefore, energy of the 180 code frequency is supplied to the relay CR and the contacts of this relay respond to energy of this code frequency and energy is inducedin the windings |23 and |24 of the decoding transformer DT. As the relay CR is responding to energy of the 58|) code frequency the frequency of the current induced in the winding |24 is such that energy from this winding is freely passed by the resonant rectier unit RUC and suiiicient energy is supplied to the winding of the relay RC to pick up this relay.

As the relay RC is picked up contact |26 interrupts the circuit of the resonant unit RUB so that energy is not supplied to the relay RB, while contact |28 interrupts the circuit of relay RA. Accordingly at this time the relays RA and RB are released and energy cannot be supplied to the relay GC. The circuit of the Winding of the relay GC is also interrupted by contact S'lC which is open at this time as the signal SA is assumed to be displaying its clear indication.

At this time contact |34 of relay RC establishes relay JC. This circuit is also controlled by contact 2B of the track relay |2TR, but as the track stretch is assumed to be vacant the contacts of this relay are picked up.

From the foregoing it will be seen that when the track stretch is vacant and the home and distant signals for the switch W are displaying clear indications, the relay RC is energized with the result that energy is supplied to the relay JC, but not to the relay GC, As the relay GC is deenergized its contact le interrupts the circuit of the aproach locking relay H so that contacts 5D and 5| of relay H are released and interrupt the circuit of the switch control relay WR to prevent changes in the position of the switch.

kIf a train moving in the normal direction of trailic, that is, from left to right, enters section MBT track relay ITR releases and interrupts the circuit for supplying energy of the 180 code frequency to the line Wires with the result that the code following relay CR ceases to respond to coded energy and energy is no longer supplied through the decoding transformer DT to the relay RC. Accordingly the relay RC releases and contact |34 interrupts the circuit of the relay JC which releases, so that even if the contacts of the relay GC Vthereafter become picked up the circuit of the approach locking relay H cannot be completed except by operation of a time release device, or of the detector locking means.

When the train enters section iT the contacts of the relayv |TR become released to additionally interrupt the circuit for supplying energy of 180 code frequency to the line wires, while when the train enters section |2T, contact 28 of relay |2TR releases and its contact 28 interrupts the circuit of relay JC to prevent establishment of the pick-up circuit of the approach locking relay.

When the train vacates sections lT and HT the track relays ITR and HTR pick up and establish the circuit for supplying energy of 180 code frequency over the line to therelay CR, while as a result of code following operation of this relay energy is supplied through the decoding transformer DT to the relay RC, and this relay picks up and supplies energy to the relay JC when section |2T is vacated and relay |2TR picks up.

When the train passes out of the track stretch and the home signal SA is again conditioned to display a proceed indication contact 31C is opened to prevent energization of relay GC to thereby prevent energization of the approach locking relay H.

'Ihe system provided by this modication is arranged so that when the track stretch is vacant the operator can secure control of the switch W by placing home signals SA and SB at stop, providing the distant signal SD operates in the intended manner to display its caution indication.

When the distant signal SD is displaying its caution indication the contact 35D is released with the result that if the track relays MTR and HTR are picked up the circuit of the |23 contact of the code transmitter CT is established, and

a circuit to supply energy to the winding of the energy of this code frequency is supplied over the line wires to the code following relay CR. When the relay CR responds to energy of code frequency energy is supplied through the decoding transformer DT and the resonant unit RUB to the relay RB and this relay picks up.

When contact |3| of relay RB is picked up the circuit for supplying energy to the relay GC is established. This circuit is complete at this time as contact 31C is closed since the signals SA and SB are assumed to have been placed at stop.

When contact |33 of relay RB is picked up the circuit for supplying energy to the relay 'JC is established. This circuit is complete at this time as the contact 28 of the track relay |2TR is picked up since the track Stretch is assumed to be unoccupied.

From the foregoing it will be seen that when the track stretch is vacant and the distant signal SD is displaying a restrictive indication energy of the l2() code frequency is supplied to the code following relay CR. In addition, it will be seen that when the relay CR is responding to energy of the 120 code frequency circuits are established to supply energy to the relays JC and GC with the result that both of these relays are picked up and establish the pick-up circuit of the approach locking relay H so that the operator has full control over the switch.

The pick-up circuit for relay H includes front Contact l of relay GC and front contact 46 of relay JC, while when relay H is picked up its contact lil establishes a stick circuit shunting contact 46 of relay JC to thereby maintain the relay H energized after a train enters the approach zone and causes release of relay JC.

When relay H is picked up its contacts 50 and establish the circuit for supplying energy to the switch control relay WR.

The circuit of the switch control relay WR is also controlled by contacts 53 and 54 of relay |3TR, and if at this time the section |3T is vacant, the circuit for supplying energy to the switch control relay WR is complete. The operator may effect movement of the switch W by moving the switch control lever L from its normal to its reverse position to thereby change the polarity of the energy supplied to the relay WR.

When the switch W has attained its reverse position the operator may condition the signal SB to display its proceed indication. The means for controlling the signal SB may be any means old and well known in the art, and has not been shown in order to simplify the disclosure.

When the signal SB is conditioned to display a proceed indication the contact 31C is opened since this contact is controlled in` such a manner as to be closed only when the signals SA and SB both display their stop indications. Opening of contact 31C interrupts the circuit of relay GC so that contact 44 of relay GC releases and interrupts the circuit of relay H and contacts 50 and 5I of relay H release and interrupt the circuit of relay WR to prevent movement of the switch.

If for any reason the distant signal SD should fail to respond in the normal manner to the change in the home signal and continues to display its clear indication after the home signal has been placed at stop, the Contact 35D will remain picked up and will maintain the circuit for supplying energy of 180 code frequency to the line wires Zlland 2|. As a result the energy supplied through the decoding transformer DT is of such frequency that the relay RC remains picked up and its contact |25 interrupts the circuit of relay RB and its contact |28 interrupts the circuit of the relay RA. Accordingly, relays RA and RB are both released and energy is not supplied to the relay GC and contact M of relay GC remains released and interrupts the circuit of the relay H to thereby prevent movement of the switch as long as the distant signal SD displays its clear indication.

From the foregoing it will be seen that when...

' the home signals are placed at stop and the distant signal SD displays its caution indication a pick-up circuit is established for the approach locking relay H and this relay establishes the circuit of the switch control relay WR to thereby permit movement of the switch. However, if the distant signal fails to respond to the change in the home signals and continues to display its clear indication the pick-up circuit for the approach locking relay HJwill not be established and this relay will remain released and interrupt the circuit of the switch control relay WR and thus prevent movement of the switch.

The operation of the equipment when it is desired to move the switch from its reverse to its normal position is substantially the same as explained above.

The system is arranged so that if while the home signals are at stop and the distant signal is at caution a train enters the approach Zone, the locking relay H will remain energized and will maintain the circuit of the switch control relay WR so that the operator retains control of the switch.

If under these conditions a train enters the approach zone the track relay IllTR will become released to thereby interrupt the circuit for supplying energy of 120 code frequency to the line wires and to establish the circuit for supplying energy of code frequency to the line wires.

On this change in the frequency of the energy supplied to the line wires and thus to the relay CR, insufcient energy is supplied through the resonant rectifier unit RUB to maintain the relay RB picked up, and its contact |21 releases and establishes the circuit to supply energy from the winding |23 to the relay`RA so that relay RA picks up and establishes a circuit to supply energy to the relay GC.

In addition, on release of relay RB its contact |33 interrupts the circuit of relay JC so contact 45 of relay JC releases and interrupts the pick-up circuit for relay H, but the relay H is maintained energized by current supplied over its stick circuit which includes its own front contact 47|.

There is a short time interval between the time at which relay RB releases and interrupts the supply of energy to relay GC, and the time at which relay RA picks up and reestablishes the supply of energy to the relay GC. The relay GC is of a type which is slow in releasing and it is selected so that its contacts will remain picked up during the time interval between release of relay RB and picking up of relay RA. At this time, therefore, the circuit of the approach locking relay I-I is maintained and this relay maintains the circuit of the switch control relay WR so that the operator may move the switch if he desires to do The system provided by this invention is arranged so that the operator can obtain control of the switch at a time when the approach zone is occupied, provided the distant signal SD is conditioned to display a restrictive indication, and provided a time interval is permitted to elapse after the home signals have been placed at stop.

If a train is present in either section lllT or I |T the track relay of the occupied section will be` released and will establish the circuit through which energy of the '75 code frequency is supplied to the line wires when the distant signal SD becomes conditioned to display a restrictive indication and contact 35D becomes released.

On the supply of energy of the '75 code frequency to the code following relay CR, energy is supplied to the relay RA and relay RA picks up and supplies energy to relay GC, assuming that the home signals are at stop so that the contact 37C is closed, and relay GC picks up to permit the pick-up circuit of the approach locking relay H to be established on closing of a contact 65 of a time element device, not shown, or on closing of contact 64 of the track relay |3TR of the detector section IST.

The time element device, not shown, may be of the thermal type disclosed in Letters Patent of the United States No. 2,114,895 of Harry E. Ashworth and is arranged so that the contact 65 is normally open and becomes closed only after the device has been energized for a predetermined time interval. This time interval is long enough to enable a train in the approach zone to be stopped, or if the train is unable to stop, to enable it to enter the detector section IST and thus render the detector locking effective before the approach locking relay H picks up.

This system makes it possible to indicate at a remote point over a single pair of line wires two separate conditions. In this system the supply of energy of 180 code frequency over the line wires indicates that the approach zone is Vacant and that the distant signal SD is displaying its clear indication. Similarly the supply of energy of the 120 code frequency to the line wires indicates that the signal SD is displaying a restrictive indication and that the approach zone is vacant, while the supply of energy of the 75 code frequency indicates that the signal is displaying a restrictive indication and that the approach zone is occupied.

Although I have herein shown and described only one form of railway traic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. In combination, a railway switch, an approach zone of track leading to the switch, a signal controlling traffic through said approach zone towards said switch, a code following relay, means effective when said approach zone is occupied and said signal is displaying a more restrictive indication to supply energy of low code frequency to said relay, means effective when the approach zone is vacant to supply to said relay energy of intermediate or high code frequency according as said signal is displaying said more or a less restrictive indication, a first, a second and a third auxiliary relay, means effective when said code following relay is responding to energy of any code frequency to supply energy to said first auxiliary relay through back contacts of said second and third auxiliary relays, means effective according as said code following relay is responding to energy of the intermediate or high code frequency to supply energy to said second and third auxiliary relays respectively, the circuit of the second auxiliary relay including a back contact of the third auxiliary relay, a rst control relay energized when either said first or second auxiliary relay is energized, a second control relay energized when either said second or third auxiliary relay is energized, a lock relay effective when deenergized to prevent movement of the switch, a circuit complete when said control relays are both energized for supplying energy to said lock relay, and a circuit over which energy may be supplied to said lock relay when said second control relay is deenergized provided the first control relay is energized.

2. ln combination, a railway switch, an approach zone of track leading to the switch, a distant signal governing traffic through said approach zone towards said switch, a code following relay, means effective when said approach zone is occupied and said signal is displaying a more restrictive indication to supply energy of low code frequency to said relay, means effective when the approach zone is vacant to supply to said relay energy of intermediate or high code frequency according as said signal is displaying said more or a less restrictive indication, a rst, a second and a third auxiliary relay, means effective when said code following relay is responding to energy of any code frequency to supply energy to said first auxiliary relay through back contacts of said second and third auxiliary relays, means effective according as said code following relay is responding to energy of the intermediate or highk code frequency to supply energy to said second and third auxiliary relays respectively, the circuit of the second auxiliary relay including a back contact of the third auxiliary relay, a home signal controlling movements of trains through said switch, a rst control relay energized when either said rst or second auxiliary relay is energized provided said home signal is displaying its stop indication, a second control relay energized when either said second or third auxiliary relay is energized, a lock relay effective when deenergized to prevent movement of said switch, a circuit complete when said control relays are both energized for supplying energy to said lock relay, and a circuit over which energy may be supplied -to said lock relay when said second control relay is deenergized provided the first control relay is energized. l

JAMES J. vANHoaN. 

